Abstract

Aberrant expression of lymphoid-associated antigens in acute myeloid leukemia (AML) exhibits geographic variability, with limited data from Middle Eastern populations, particularly Yemen. We conducted a retrospective analysis of flow cytometry data from 24 AML patients diagnosed at a tertiary Yemeni cancer center between January 2025–December 2025. Immunophenotyping was performed using a standardized 25-marker panel, with aberrant expression defined as ≥20% blast positivity. The AML cohort comprised 24 patients (median age 28 years, range 1–85; M:F 1.4:1). Aberrant CD56 and CD7 expression was observed in 29.2% (7/24) and 25.0% (6/24) of AML cases, respectively. Co-expression of CD56 and CD7 occurred in 16.7% (4/24). CD56 positivity was significantly associated with monocytic differentiation (AML-M4/M5 subtypes; 85.7% vs. 35.3%, *p*=0.01). CD7+ cases exhibited higher peripheral blast percentages (median 97% vs. 70%, *p*=0.03) and lower platelet counts (median 22 vs. 65 ×10⁹/L, *p*=0.02). For comparison, data from 16 B/T-ALL and 2 MPAL cases from the same period are also presented. Yemeni AML patients display a distinct immunophenotypic profile characterized by frequent aberrant CD56 and CD7 expression, forming a unique subgroup with potential clinical and prognostic relevance. These findings underscore the importance of population-specific immunophenotyping and highlight regional biological variations in AML.

Keywords

acute myeloid leukemia, immunophenotyping, CD56, CD7, aberrant antigen expression, Yemen